Updating the machine

[Target]

My CPU is 4 years obsolete, SH3 runs smooth most of the time. My MultiSync 75 is 7 years old. My sound is a cannabilized Gateway SB Live value card (digital). I've never really gotten up to speed at anytime when purchasing a PC. Always looking for the "deal" when upgading, which means the computer has been behind the tech curve. So this time I'm thinking that I'd like to be able to experiance the new games coming out at peak performance and graphical detail. I know squat about these things, so building my own won't do. Of course, how much I spend can be relative to how good the machine is, but I do have other responsibilities as well. So balance is the watchword. Can someone give me some thoughts on this machine? SH4 will be the main event but I also like flight sims and FPS. Thanks.
http://www.alienware.com/product_detail_pages/Area-51_7500/area-51_overview.aspx?SysCode=PC-AREA51-7500-R4&SubCode=SKU-A

[flintlock]

There were too many hardware question and upgrade query threads, so all of them have been merged and stickied within this thread:

http://www.subsim.com/radioroom/showthread.php?t=105845

[trenken]

Alienware makes good machines. Here's a couple more you might be interested in. Might be able to get a better deal elsewhere.

http://www.dell.com/content/products/productdetails.aspx/xpsdt_710?c=us&cs=19&l=en&s=dhs

http://www.falcon-nw.com/